Your account nice but rank poor.
I think you should post in lol forum, that may more customer then here.
I don't think that the account has a poor rank, with gold you get the skins + a border from the previous season.
Account is currently unranked and I won't rank it.
There are golds that are bronze this season. I think if you rank the account it'll be easier to determine the price value.
I didnt play league for quiet a while, so this would turn out bad I am sure.
Account was Platinum 2-3 When i quit, then it deranked slowly to Gold until the end of the season.
Account should have decent ELO.